Method for preparation of aliphatic di- or poly-hydroxy-arsonic acids



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Patented Dec. 27, 1927.

UNITED STATES PATENT OFFICE.

CARL T. OECHSLIN, OF ABLON, FRANCE.

METHOD FOR PREPARATION OF ALIPHATIC IJL 0R POLY-HYDROXY-ARSONIG ACIDS.

No Drawing. Original application filed September 14, 1922, Serial No. 588,182, and in France December 29, 1921. Divided and this application filed January 26, 1925.

As stated in my application Serial No. 588,182, filed September 14, 1922, of which the present application is a division, the best method of preparing 1nethyl-ethyl-arsonic acids and the like consists in causing the allcyl-halogens to act upon sodiuin arsenite.

The discovery has been made that sodiuin arsenite can also he acted upon by aliphatic products containing in the same molecule one or more halogens and one or more hydroiiyl groups. The present application is concerned with the diand polyhalogenhydrins For example, the dichlorohydrin of glycerol. I

The proportions between the arsenious acid and the dior polyhydrin, and between the caustic soda and the arsenious acid, can be varied within rather wide limits. The temperatures of the reaction may also be varied accordingly.

Example 645 grains of glycerol dichloroliydrin are added to a solution of 100 grains of arsenious acid in 262 c. c. oi 38% caustic soda solution and heated to 80 degrees 0., the solution being stirred during the heating About halt an hours time is required to complete the reaction Upon acidulation, crystallization oi a product OHgr-ABOtOHM UHOH L 11l -ils()(O]-I); obtained. This product is dissolved in the original reaction solution in the form oil? a salt. Upon acidification, liydii'orypropyldiarsenic acid is liberated and as it is in soluble in miter it crystallizes out of the so l utiou. it

Recrystallization with alcohol is then perloruiedu Serial No 4,914.

The residue is the product on on (IJHOH ()Hz-ils0(0ll) The above compound remains in the orig inal reaction solution and crystallizes there from after the hydroxypropyl-diarsenic acid.

Having now particularly described and ascertained the nature of my invention, and in what manner the same is to he performed, 1 declare that what 1 claim is:

l. The method of preparing aliphatic 11y droryarsonic acids by the action of an lraii metal arseuite upon an aliphatic dihalogcii-hydrin, and decomposing the resulting alkali metal salt with acid.

2. The method of preparing aliphatic hydroriy-arsonic acids by the action out an alkali inetal ursenite upon an aliphatic polyhalOgeIi-liydrin, and decomposing the result-- ing alkali metal salt with acid 3. The method ol preparing aliphatic hy droxy-arsonic acids by the action oi an alkali metal arsenite upon an alipltiatic polyhalo gen-polyhydriiu and decomposing the result-- lug; alkali metal salt with acid 4h The method of preparing the hydrox arsenic acids represented by the formulae which consists in treating glycerol dichlo" rohydriiu with arsenous acid in caustic soda solutioi'i, with heating and stirring and suhsequeut isolation oi the tree acid by acidi lication, extraction with alcohoh and evapo ration of the solvent.

(lAl'tl'i J 0 ill CH SL1 N;

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